Zuckerberg also expressed concerns that the outcry about vast secret spy programs run by the National Security Agency and the U.S. response could alienate other countries and hurt innovation globally. In San Francisco last week, Zuckerberg said the government "blew it" on the spy programs.
"Response to the NSA issues that have blown up are a big deal for the Internet as a global platform. And some of the government statements I think have been profoundly unhelpful," he said.
"'Oh, we only spy on non-Americans.' Gee thanks," Zuckerberg said, adding, "We're trying to provide an international service, not get crushed in those places either."
(Read more: US spied on Google, Brazil's Petrobras: Report)
Earlier this year, Facebook said some 1.1 billion people around the world used its site each month.
The tech sector has been pushing for more disclosures about government data requests as Internet companies seeks to shake off the concerns about their involvement in vast secret U.S. surveillance programs revealed by former spy contractor Edward Snowden.
Earlier this month, Facebook joined Yahoo!, Google and Microsoft in asking the Foreign Intelligence Surveillance Court for freedom to disclose aggregate data about the orders and requests for information they receive under the Foreign Intelligence Surveillance Act.
On Wednesday, Zuckerberg said the revelations about U.S. online surveillance had a much bigger impact on users' trust in Facebook than any criticisms related to the company's own privacy policies.
Priority on immigration
The issue that brought California-based Zuckerberg to Washington was his push for immigration reform, which has prompted him to wade deep into political waters.
This year, he founded an advocacy group, FWD.us, that lobbies for a comprehensive immigration reform, promoting the concept of building a "knowledge economy." The group has come under fire for ads that backed pro-immigration lawmakers on issues unrelated to immigration, such as oil drilling.
"We just want to be there to help support folks who are going to have to take challenging positions on something that's going to be controversial but they ultimately believe is the right thing," Zuckerberg said.
(Read more: Facebook joins the $100 billion club)
He was scheduled for sitdowns on Thursday with Republican House Speaker John Boehner and Democratic House Leader Nancy Pelosi as the House of Representatives poses an uphill battle for the immigration legislation, which already has been passed by the Senate.
Zuckerburg, who ditched his signature hooded sweatshirt and blue jeans in favor of a dark suit and tie on Wednesday as he made his way through the hallways of Congress, said he was optimistic the legislation's chances.